Nearline cloud storage based on fuse framework

ABSTRACT

In one example, a method includes receiving, from a client, a request for file system information, transmitting the requested file system information to the client, receiving, from the client, a request for data that includes a portion of a file that resides at the datacenter, where the file is compatible for use by an application residing at the client, where the request for data specifies a particular byte range associated with the file, and where the byte range spans a group of different backups of a baseline dataset residing at the datacenter. The example method further includes creating a virtual synthetic that is formed by the data in the requested byte range and includes respective portions of data from each of the group of backups residing at the datacenter, and transmitting the virtual synthetic to the client.

RELATED APPLICATIONS

This application is a continuation of, and hereby claims priority to, U.S. patent application Ser. No. 14/578,162, entitled NEARLINE CLOUD STORAGE BASED ON FUSE FRAMEWORK, and filed Dec. 19, 2014. All of the aforementioned applications are incorporated herein in their respective entireties by this reference.

FIELD OF THE INVENTION

Embodiments of the present invention generally concern mechanisms for enabling user access to data stored at a datacenter. More particularly, at least some embodiments of the invention relate to systems, hardware, computer-readable media, and methods for creating and using a virtual synthetic that enables direct user access to datacenter data without the need to download datacenter files to the local machine of the user.

BACKGROUND

Entities often generate and use data that is important in some way to their operations. This data can include, for example, business data, financial data, and personnel data. If this data were lost or compromised, the entity may realize significant adverse financial and other consequences. Accordingly, many entities have chosen to back up some or all of their data so that in the event of a natural disaster, unauthorized access, or other events, the entity can recover any data that was compromised or lost, and then restore that data to one or more locations, machines, and/or environments.

Increasingly, entities have chosen to back up their important data using cloud based storage. The cloud based approach to backup has proven attractive because it can reduce, or eliminate, the need for the entity to purchase and maintain its own backup hardware. Cloud based storage is also flexible in that it can enable users anywhere in the world to access the data stored in the cloud datacenter. As well, the user data is protected from a disaster at the user location because the user data is stored in the cloud data center, rather than on backup hardware at the user location.

While advantageous in certain regards, the use of cloud based storage has introduced some new problems however. For example, some cloud based storage systems and services require that a user download an entire file from the datacenter to the local user machine before the user can fully access that file. Depending upon the size of the file and the capacity of the communication line connecting the user with the datacenter, this process can be unacceptably long.

To illustrate with an example, in order for a user to attempt to locally start up a 100 Gb GB virtual machine (VM), and assuming a T3 line (having a capacity of about 44 Mbps) connecting the user with the datacenter where the VM is stored, the user would have to wait approximately 5 hours for the VM to be transferred from the datacenter to the local user machine over the T3 line. In many circumstances, such a transfer time is unacceptably long.

A related consideration is that while the entire file is downloaded in circumstances such as those noted above, it may be the case that the user does not need the entire file. To continue with the previous example, it can be the case that only about 500 Mb of data is needed to boot a Windows® host. Thus, over 99 percent of the data that was transferred to the user in this example was not actually needed by the user to boot the VM, and the download time for only the data actually required to boot the VM could be reduced to about 90 seconds. This example accordingly demonstrates that bandwidth is unnecessarily consumed by transferring data that is not needed by the user. Thus, not only is user access to datacenter files significantly slowed, but the data transfer bandwidth of the system is inefficiently utilized.

In light of problems and shortcomings such as those noted above, it would be useful to enable a user to directly access data stored at a datacenter, rather than having to first download the data locally in order to be able to access that data. More particularly, it would be useful to be able to identify and download only the data actually needed by a user who has requested access to data stored at a datacenter. It would also be useful to be able to represent datacenter data to a user in such a way that the datacenter data appears to the user as a local file system, for example, on the user machine. Finally, it would be useful to be able to provide these functions, among others, in a variety of scenarios and use cases, examples of which include disaster recovery, and live access to databases, email repositories, and other data sources.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which at least some aspects of this disclosure can be obtained, a more particular description will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only example embodiments of the invention and are not therefore to be considered to be limiting of its scope, embodiments of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

FIG. 1 is directed to aspects of an example operating environment for at least some embodiments;

FIG. 2 is directed to an example implementation of a computing device, such as a host, that may be employed with at least some embodiments;

FIG. 3 is an example of a scheme for backing up data;

FIG. 4 is a flow diagram disclosing aspects of a method for backing up data;

FIG. 5 is a flow diagram that provides additional information concerning aspects of the example method of FIG. 4; and

FIG. 6 is a flow diagram disclosing aspects of FUSE-specific methods.

DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS

Embodiments of the present invention generally concern systems, hardware, computer-readable media and methods for performing disaster recovery and restore operations in environments, such as cloud environments, for example, that include a datacenter where one or more backups are stored and where there is a need to provide direct user access to data stored in the datacenter. For example, one or more clients, which can be cloud based computing systems and/or customer sites, communicate with one or more backup servers of a cloud based datacenter to access backed up data stored at the datacenter.

When a disaster or other event occurs that compromises or renders locally stored data inaccessible or unusable, there is a need to quickly and efficiently provide users with access to the backup of that data until such time as the lost or compromised data can be locally restored. To this end, example embodiments disclosed herein enable a user to directly access data stored in a cloud based datacenter. As well, such embodiments can eliminate the requirement to download entire user data objects such as files, file structures, or other datasets, as a prerequisite to user access to the data. More specifically, such embodiments enable a user to identify and download from the datacenter only that data that is necessary for operations desired to be performed by the user with an application. In this way, the relative size of downloads needed may be reduced, and the relative speed with which such downloads can be implemented may be increased.

At least some embodiments are implemented in connection with a datacenter in the form of cloud based storage. The cloud datacenter may be accessible to one or more cloud clients and/or to one or more customer sites. As well, the cloud datacenter may be directly accessible by cloud clients and customer sites or, alternatively, the cloud clients and/or customer sites can access the cloud datacenter by way of an intermediate network.

The cloud datacenter can provide encryption and compression services, although neither is necessarily required. In some embodiments at least, all data stored by the cloud datacenter, and communicated by the cloud datacenter to the user, may be in encrypted form so that that the user can be assured of data integrity and security.

In one example embodiment, a file system tool residing on a user machine can be used to initiate a process to enable a user to access datacenter data. Among other things, the file system tool can operate in connection with an interface module at the user machine to communicate with the datacenter and present datacenter data to the user in such a way that the data appears to the user as, for example, a local file system, notwithstanding that the data actually resides at the cloud datacenter. Once the datacenter data is presented in this fashion, the user can then select, using a browser, for example, a desired dataset, or datasets, to be accessed.

As well, the file system tool enables a user to identify one or more datasets of interest, such as a set of files as those files existed at a particular date/time, associated with an application. The file system tool can also mount the requested datasets at the client. Once the dataset(s) of interest have been mounted, the file system tool translates filesystem requests by the application into requests to the datacenter for one or more byte ranges, for example, of a dataset used by the application. By way of example, the tool can interface with a mail system, such as MS Exchange®, to request that a particular mailbox, or portion of a mailbox, be downloaded from the datacenter. Such datasets could include any data of interest to a user, such as, for example, a database, file structure, a file, a virtual machine file such as a .VMDK (virtual machine disk file developed by VMware), or any other data object(s) to which the user requires access. In one particular embodiment, the tool can identify and request specific data at the block level, and/or byte range.

When the datacenter receives the user data request, the datacenter can then retrieve the requested data, which may be a specific file, or only a portion of a file, for example. In one particular example, the datacenter retrieves the file as the file existed at a particular point in time. As such, the file or file portion may reflect any number of incremental changes that have been made between the time the file or file portion was first stored at the datacenter and the time that the file or file portion was retrieved by the user.

Where the portion of a file or other dataset requested by the client does not exist on its own as a baseline, it may be referred to as a virtual synthetic. That is, the portion that is mounted is synthetic in the sense that the portion is created, or synthesized, on an ad-hoc basis according to user requirements and the portion does not exist separately on its own at the datacenter. Further, the synthetic is referred to as virtual because it is presented, and appears, to a user as though the synthetic does separately exist.

In at least some embodiments, the datacenter can employ a manifest that lists various types of datasets that can be retrieved, either in whole or in part, by a user. As noted above, such datasets could include, for example, a database, a file structure, and various types of individual files such as .VMDK files, and mailbox files. A table of contents at the datacenter includes one or more entries for each file. Each entry is associated with a mapping that identifies, for example, a byte range associated with a file, where the bytes of the byte range are stored in the data center or are derivable at some offset in a prior version of the file, and compression information associated with bytes of a byte range. The datacenter can use the manifest and table of contents to identify, locate, and return the requested portion of the file synthetically to the user.

In at least some embodiments, part or all of the requested data is cached at the user machine. Where the file is relatively small, the entire file can be downloaded on the client machine. However, where the file is relatively large, only those portions of the file actually needed by the user are downloaded to the user machine. Advantageously then, a relative reduction in transmission bandwidth, and transmission time, can be achieved with embodiments of the invention.

As suggested above, the datacenter can receive, store, and transmit data in an encrypted form to help ensure the integrity of the data. Because the data is always encrypted, and only the user has the decryption key, the user has some assurance that there will be no unauthorized access to the data. Accordingly, the data requested and received by the user may require decryption and decompression after the file has been mounted. Once any decryption and decompression have been performed, the associated application at the user location can then access and manipulate the retrieved file portions.

Finally, any changes to the file can be locally cached and/or returned to the datacenter, and the manifest and table of contents at the datacenter updated accordingly. The changes can be compressed and encrypted prior to transmission to the datacenter.

A. Example Operating Environments

In general, embodiments of the invention may include and/or be implemented in an operating environment that includes one or more clients and one or more backup servers. As used herein, the term client is intended to have broad scope and embraces, among other things, any system, device, or combination of those, by way of which direct access to cloud based storage can be achieved. As such, one or more clients may be in a cloud system, and/or one or more clients may be located at a customer site. Similarly, the term backup server is intended to have broad scope, and embraces, among other things, any backup server and associated storage device or system that are located remotely relative to a client. As such, one or more backup servers may be part of a cloud based storage system, such as a cloud datacenter, for example.

With attention now to FIG. 1, details are provided concerning some operating environments, one example of which is denoted at 100, in connection with which various embodiments of the invention may be employed. In FIG. 1, the example operating environment 100 may be a network such as a local area network, a wide area network, the internet, or any other networked configuration. Moreover, the operating environment 100, or any group of one or more of its elements, may comprise, form an element of, or constitute, a cloud computing environment. The environment 100 may include various devices including servers and other computers that are interconnected. The operating environment 100 may employ a variety of communication media, such as hardwire, wireless, or some combination thereof. In some instances, some or all of the operating environment 100 may comprise an optical communication network.

As indicated in FIG. 1, the example operating environment 100 includes a cloud datacenter 200 that may include one or more cloud datacenter servers, such as datacenter servers 200 a, 200 b and 200 c. For the purposes of the discussion, only datacenter server 200 a will be discussed but it should be understood that datacenter servers 200 b and 200 c may be similar, or identical, to datacenter server 200 a in terms of operation and/or configuration. In at least some embodiments, two or more of the datacenter servers 200 a-200 c can communicate with each other, although that is not required. In general, the datacenter server 200 a is implemented as a backup server that is able to communicate with one or more clients 300 a and 300 b, either directly or by way of an a communications network 400, to transmit data to, and receive data from, the clients 300 a and 300 b. Examples of backup servers include, but are not limited to, the EMC Avamar server, and the EMC NetWorker server.

With continued reference to FIG. 1, further details are provided concerning the example datacenter server 200 a. As indicated, the datacenter server 200 a may include a backup and restore application 202 that cooperates with a file system tool, discussed below, residing on one or more clients such as clients 300 a and 300 b, to restore requested data to the clients. The datacenter server 200 a also includes, or has access to, storage 204 that stores backup data for one or more clients. The data stored for each client can include one or more backups of that client, or a portion of that client.

To facilitate management of backup and restore processes, including the generation and presentation of virtual synthetics, the datacenter server 200 a may also include a manifest 206 and a table of contents 208. A manifest 206 and table of contents 208 can be provided on any number of different bases including, for example, for each client, or for each backup of a client or client file. It should be noted that metadata concerning data residing at the datacenter is not required to also reside at the datacenter. For example, the table of contents 208 and/or manifest 206 can, more generally, be stored anywhere that is accessible by a file system tool, examples of which are discussed in more detail below.

With reference first to the manifest 206, the manifest 206 may be generated at the time a backup is created. In general, the manifest 206 may take the form of a listing of various types of information and data structures that have been backed up. Thus, in the illustrated non-limiting example, the manifest 206 lists a database, a .VMDK file, a mailbox, a file, and one or more various other backed up information and/or data structures. In general, any material(s) capable of being backed up and restored can be included in the manifest 206, and there are no constraints, for example, as to the type, size and number of information and data structures that can be reflected in the manifest 206. In at least some particular embodiments, relatively large files such as virtual machine disk files, databases and mailbox files are listed in the manifest 206.

As noted earlier, the cloud datacenter server 200 a may also include a table of contents 208. In general, the table of contents 208 serves to keep track, such as by mapping, for example, of incremental changes that have been made to information listed in the manifest 206 and stored by the datacenter server 200 a. For example, the table of contents 208 may include entries 208 a, 208 b and 208 c that including information concerning, respectively, a file, information, and a data structure. Each of the entries can include various types of information concerning the data with which that particular entity is associated.

For example, an entry 208 a may include a mapping that indicates the byte range, in storage, that is spanned by the file to which the entry 208 a corresponds. As well, the mapping could also indicate other information, such as where the bytes of that byte range are stored, the type of compression and/or encryption used on those bytes, and any other information concerning the bytes of the file.

As well, the table of contents 208 may provide mapping to one or more incremental changes 210, or simply incrementals, to any of the entries in the table of contents 208, such as the entry 208 a, for example. That is, the table of contents 208 can reference one, some, or all, of the incremental changes that have been made over time to the file to which entry 208 a corresponds. Among other things, this approach can enable a user to request a file, or other information, as that file or information existed at a particular point in time. In the particular example of FIG. 1, the table of contents 208 maps to the original file version 210 a, and also maps to first and second incrementals 210 b and 210 c, respectively. Each of the incrementals 210 represents a different set of changes to the file to which entry 208 a corresponds, and each of the incrementals 210 corresponds to a different respective point in time. Moreover, and as suggested in FIG. 1, each of the incrementals 210 is relatively smaller in size than the file to which the incremental 210 corresponds. Thus, when a file version is requested, the entire file need not be sent to the requestor. Instead, only the incremental changes through the date of interest are required to be sent.

With continued reference to FIG. 1, and as noted earlier, a cloud datacenter including one or more datacenter servers may communicate with one or more clients, two examples of which are denoted at 300 a and 300 b, respectively. As the clients 300 a and 300 b may share a number of similarities, only client 300 a is addressed in the following discussion.

Among other things, the client 300 a may include one or more applications 302 a, a local cache 304 a, a file system tool 306 a with a FUSE module 308 a, a web interface/API 310 a and local storage 312 a. With reference first to the applications 302 a, example applications include, but are not limited to, word processing, email, a backup and restore client, database management, and any other application(s) capable of generating data that can be backed up at the cloud datacenter 200. As discussed in more detail elsewhere herein, one or more of the applications may directly or indirectly request data from the cloud datacenter 200 and the requested data can be stored in the local cache 304 a when received by the file system tool 306 a of the client 300 a. In at least some instances, requests for data from the cloud datacenter 200 can be formulated by the file system tool 306 a, particularly the FUSE module 308 a in some embodiments, and transmitted by way of a web interface/API 310 a/310 b using an application program interface (API) such as the RESTful (REpresentational State Transfer) HTTP-based API, although other mechanisms can be used instead of the RESTful HTTP-based API. More generally, backend storage can be any cloud API that supports requesting specific ranges of content from a datacenter or other data repository.

The file system tool 306 a can be specific to a particular application or types of data. In some other embodiments, the file system tool 306 a can be generic, and as such, may not need to have knowledge of the contents of the data that is being requested from the client side, discussed below.

The FUSE module 308 a, which could take the form of a plug-in, can be used by the file system tool 306 a to provide the user with a representation of a virtual file system that includes representations of the files of the user that are stored at the cloud datacenter 200. That is, the file system tool 306 a can use the FUSE module 308 a to create and present a standard file system interface that represents a FUSE file structure that has a live connection to a virtual synthetic. As such, the standard file system interface thus created and presented may be referred to herein as a FUSE interface. Thus, when this file system interface is presented to a user at the client, the user can access the FUSE file structure by way of the file system interface to perform operations concerning the virtual synthetic.

This FUSE interface may have both visual and functional aspects. To briefly illustrate, the representation could appear to the user as a display of a virtual file structure. In one particular embodiment, the FUSE module can be implemented in the form of a file system driver, such as the Filesystem in Userspace (FUSE) operating system mechanism, although other drivers, mechanisms and interfaces could alternatively be employed. As well, one example of a file system tool 306 a may be referred to herein as a Data Protection Cloud File System (DPCFS).

As noted above, the file system tool 306 a can operate in connection with the FUSE module 308 a to request, using the FUSE module 308 a, for example, the specific data needed at the client. More specifically, such a request can specify a particular file and one or more byte ranges, or any other type of data range, associated with that file that is needed for access at the client. Additionally, or alternatively, the file system tool 306 a can define, or direct the definition of, these data requests, and these operations of the file system tool 306 a can be performed in whole or in part by the FUSE module 308 a.

In one particular example, a request may identify a file or file system as it existed on a particular date, and even at a particular time on that date. The file or file system, as applicable, has an associated byte range so that when this information is received at the datacenter, the datacenter can use the associated byte range to identify which incremental(s) apply and, thus, identify the data that should be returned to the requesting client. As the foregoing example illustrates, a desired byte range can be specified, either explicitly or implicitly, using criteria such as the date of a particular version of a file.

The file system tool 306 a not only identifies and requests data needed by the user but can also make the requested data available at a client by way of a virtual file structure interface that can be created, for example, by the FUSE module 308 a. In at least some embodiments, the data is provided from the datacenter only to an authorized client, or clients. This approach can help to ensure data integrity and security.

After the requested data has been made available at the client, the file system tool 306 a, responding to user commands that may be provided by way of the FUSE module 308 a, for example, can perform or cause the performance of a variety of file system operations, examples of which include, but are not limited to, open, view, search, read, write, move, and delete.

In addition to these operations, the file system tool 306 a can perform, or cause the performance of, a variety of other operations that may, or may not, be specifically requested by the user. Such other operations can include, for example, creating a manifest, submitting changes to an existing manifest such as manifest 206, submitting changes to a table of contents such as the table of contents 208, and defining and transmitting a request to provide and mount a remote file system that represents user data. Yet other operations that can be performed by, or at the direction of, the file system tool 306 a include, for example, compression, encryption, decompression, decryption, and deduplication.

In connection with the file system tool 306 a in particular, and the components of FIG. 1 in general, it should be understood that the allocation of functionalities disclosed herein is provided only by way of example. Thus, in other embodiments, the functionalities disclosed herein for a particular client or datacenter can be allocated in any other way amongst the various elements of that particular client or datacenter, and the example functional allocations disclosed herein are not intended to limit the scope of the invention in any way.

B. Example Host Configuration

Any one or more of the clients 300 a, 300 b, and cloud datacenter server 200 a can take the form of a physical computing device, one example of which is denoted at 500. In the example of FIG. 2, the computing device 500 includes a memory 502, one or more hardware processors 504, non-transitory storage media 506, I/O device 508, and data storage 510. As well, one or more applications 512 are provided that comprise executable instructions. Such executable instructions can take the form of one or more of a backup application, and a backup client, for example.

C. General Aspects of a Backup Scheme

With attention now to FIG. 3, details are provided concerning an example scheme for backing up data. The scheme can be implemented in connection with a backup history. As noted elsewhere herein, embodiments of the invention can be advantageous insofar as they enable a client to directly access datacenter backup data, such as after a disaster has occurred, while avoiding the need to download entire files or other datasets to the client from the datacenter. More particularly, a user may only have to download parts of a dataset of interest.

In the example of FIG. 3, a backup history for a dataset, which could be a file, a file structure, a byte range, or any other dataset of any size, is indicated generally at 600. In general, the backup history 600 includes a baseline dataset 602 that in this illustrative example includes four blocks, namely, 602 a (1), 602 b (2), 602 c (3) and 602 d (4). In some embodiments, these blocks may be referred to as chunks of data. As well, the pieces or chunks of data may have a size that is variable. The four blocks of data 602 a-602 d collectively define a corresponding data range, which can be expressed in terms of bytes, namely, a byte range 604, but can alternatively be expressed in any other suitable terms. The baseline dataset 602 reflects the content of a particular dataset as that particular dataset was initially backed up at a datacenter, such as a cloud datacenter, for example. This initial backup of the baseline dataset 602 is indicated as having occurred at time to.

Over a period of time, one or more changes may be made, by an application, for example, relative to the baseline dataset 602. Each change can be backed up at the datacenter, so that the changes accumulated over time collectively define the backup history 600 associated with the baseline dataset 602. As indicated in FIG. 3, the entire updated dataset need not be stored. Instead, only the changes to the preceding version of the dataset are stored, in a form referred to as an incremental backup, or simply an incremental. Thus, the amount of storage space required to save the backup history 600 is significantly smaller than if updated versions of the entire baseline dataset 602 were required to be stored.

Any number ‘n’ of incrementals associated with the baseline dataset 602 can be created and stored. In the example of FIG. 3, an incremental ‘n’ is stored at the datacenter at a time t_(n) that is subsequent to time to when the baseline dataset 602 was stored. The incremental ‘n’ includes only two blocks, namely, blocks 606 a and 606 b. This reflects the fact that changes have been made to only two blocks associated with the baseline dataset 602. In particular, the changed version of block 602 b (2) is block 606 a (2′) and the changed version of block 602 d (4) is block 606 b (4′). FIG. 3 also indicates that the relative size of the blocks can change as modifications, reflected by incremental ‘n,’ are made.

As the foregoing example illustrates, and discussed in further detail below, a user requesting access to a dataset as it existed at time t_(n) need only be sent blocks 606 a and 606 b from the datacenter, since no changes have been made, as of time t_(n), to the other blocks associated with the baseline dataset 602.

D. Example Request and Retrieve Methods

While, as noted elsewhere herein, embodiments of the invention may be advantageous at least inasmuch as a user does not need to download entire datasets such as files or file systems, the user nonetheless needs a mechanism that allows the user to interact with data stored at the datacenter so that the user can perform desired operations concerning the backed up data. Such operations may be necessary when, for example, a disaster has occurred and the user does not have access to local data. Such operations can also be performed during normal operating conditions.

With the foregoing points in mind, an example method denoted in FIG. 4 at 700 begins when a user at a client machine requests 702 file system information from the datacenter. The requested file system information can be any information concerning a file system with which a file of interest to the user is associated. For example, the file system information could include aspects of a standard file system interface, such as one or more of a file structure, directories, and filenames. At 704, the file system information request is received at the datacenter server and at 706, the requested information is gathered and transmitted to the client.

Next, the file system information is received and presented, by way of a browser, for example, at the client 708. The file system information can be presented in the form of a file system interface, for example, but that particular form is not necessarily required and any other form that enables a user to perform file system operations such as open, view, search, read, write, move, and delete can alternatively be employed.

The file system information received from the datacenter server can be presented to the user as a virtual display. That is, the file system information can be presented 708 to the user at the client in such a way that it appears to the user that the datacenter file system is located locally at the client when, in fact, the file system is actually located only at the datacenter server. One advantage of this approach is that it eliminates the need to download an entire file structure to the client.

After the file system information has been presented 708 to the user at the client, the user can then perform 710 various file system operations concerning files and other datasets that are presented as part of the file system information. These operations can be performed in conjunction with an application and/or with a file system tool. By way of illustration, an user can write to a document using a word processing application such as MS Word®, or a user can read an email using MS Exchange®. As well, a file system tool can enable a user to perform file system operations such as move, delete, or rename, for example, regarding one or more files. The performance of file system operations is coordinated 712 with the datacenter server.

As disclosed elsewhere herein, one advantage of at least some embodiments is that file system operations can be performed at a client without the need to download the entire file in connection with which the user intends to perform such file system operations. This process, denoted generally at 710/712 in FIG. 4, is addressed in more detail below in the discussion of FIG. 5.

In any case, after a user has performed the desired file system operations, any changes to the data associated with those file system operations can then be uploaded 714 to the datacenter server. After receipt 716 of the changes to the data, the datacenter server can then update 718 a table of contents and a manifest associated with the file, database, or other dataset, with which the changes are concerned. Finally, at 720, the datacenter can coordinate with the client to dismount the file system data that was transferred, as part of 710/712, from the datacenter server to the client. After the file system data has been dismounted from the client, the user no longer has access to that data at the datacenter server, although file system data may still persist in a local cache at the client.

With reference now to FIG. 5, further details are provided concerning a method 800 for the performance, by cooperation of the client and datacenter server, of file system operations, and concerning the associated interaction between the client and the datacenter server, first introduced in connection with processes 710/712 of FIG. 4. It should be noted that as the term ‘operations’ is used herein, that term is intended to be broad in scope. As such, operations are not necessarily concerned only with modifications to a dataset, but may relate to manipulations of the dataset, such as restore operations, that do not involve changes to the content of the dataset, such as moving or renaming a dataset without modifying the dataset content. As another example of operations that can be performed in connection with embodiments of the invention, a dataset such as a .VMDK file may not be modified, but simply locally restored, such as by being mounted on a client, so that the user can use that .VMDK file to locally boot the VM to which the .VMDK file pertains. This process of local restoration may be performed, for example, when the local copy of the .VMDK file is not working properly, or at all. Other example operations concerning datasets, such as files, for example, are disclosed elsewhere herein.

The method 800 can begin at 802 when a user at a client accesses a manifest, by way of a browser, for example, to view the available version(s) of datasets, such as files, that are listed in the manifest. The user can then select 804 the desired dataset(s) from the manifest. The dataset(s) can be selected based on various criteria. One such criterion is a particular cutoff date/time. In particular, the user can specify that he would like all datasets as they existed as of the cutoff date/time. As another example, the user can specify that he would like all datasets created before, or after, a particular time. A file system tool, embodiments of which are disclosed herein, is then used to mount 806 the selected dataset(s) at the client. In some instances at least, all of the datasets listed in the manifest can be mounted. The mounted datasets can include incrementals and/or a baseline dataset.

Once the dataset(s) of interest are mounted at the client, the user opens and runs 808 an application in anticipation of performing one or more operations concerning the mounted dataset(s), such as a file, for example, with which the application is associated. As part of the operations of the application, the application can access various mounted datasets as virtual synthetics. Thus, a file system request by the application can be translated by the file system tool into a request 810 for particular byte ranges or blocks of a mounted dataset is transmitted to the datacenter server by way of a suitable interface, such as a REST API, for example.

In some instances, a number of additional bytes on either side of the byte range may be returned by the datacenter, whether or not those additional bytes were specified by the request 810. As the foregoing makes clear, the datacenter can support client requests for mounting a file as that file existed at a particular date/time, and the datacenter can also support block level and byte range requests from the client.

In at least some embodiments, the use of an FUSE module in the form of a file system driver, such as the FUSE operating system mechanism, for example, can be used to specify one or more byte ranges, or other types of data ranges. In such embodiments, the interface module may be particularly referred to as a FUSE module.

In at least some embodiments, the file system tool at the client may first check the local cache to see if some or all of the bytes in the byte range to be requested are already present locally. By performing this check, the amount of data that may be needed from the datacenter server may be reduced if the local cache already includes some of that data. Moreover, even if this check is not performed, the datacenter can inform the file system tool at the client that at least some of the data in the requested dataset has already been transmitted to the client, and the datacenter can inform the file system tool where else that data appears in the file with which the dataset request is concerned.

After the dataset request is received at the datacenter server, the datacenter server can then search 812 a manifest and table of contents to determine the location of the requested byte range. The datacenter server can then assemble, potentially from multiple incrementals and/or a baseline dataset, and return the requested data and transmit 814 the requested data to the client. Where the file or other dataset that is mounted on a client device is synthesized from multiple baseline and incremental change sets, that portion may be referred to as a virtual synthetic. That is, and as noted elsewhere herein, the file that is mounted is synthetic in the sense that the portion is created, or synthesized, on an ad-hoc basis according to user requirements and the file does not exist separately on its own at the datacenter.

In at least some embodiments, the dataset transmitted from the datacenter server to the client is in an encrypted and compressed form so that only an authorized user with an appropriate key is able to access the dataset. In at least some embodiments, access to the dataset can be confined to a particular user and client. Thus, after receipt 816 at the client of the requested byte ranges or blocks, one embodiment of the method 800 includes decryption and decompression of the received data. As well, the data transmitted from the datacenter server to the client may be de-duplicated data. In at least some embodiments, one, some, or all of decryption, decompression, and deduplication can be performed by, or at the direction of, the file system tool.

The received dataset can be stored at the client, in a local cache, for example. The storage of the dataset can be performed, for example, by the application in connection with which the request for the dataset was made. Thus, for example, if the request was made for a mailbox, or an individual email, the received dataset can be cached by the file system tool. At 818, the user can perform various file system operations concerning the cached data. As disclosed elsewhere herein, such file system operations can include, for example, reading from, and writing to, the cache. As another example, the user can employ the cached data to boot a virtual machine, as in the case where the cached data relates to a file such as a .VMDK file.

Once the user has completed the process of making changes to the cached data, the changes can then be transmitted 820 to the datacenter server for backup. This backup can be performed with any suitable backup client and backup application, and the data to be backed up can be compressed and encrypted prior to transmission from the client to the datacenter server. The received changes are then backed up 822, in the form of an incremental in at least some embodiments, at the datacenter server. As part of the backup process 822, the client can request creation or modification of the manifest, and the client can also request updates to the table of contents.

The dataset and changes stored in the local cache at the client may remain in that cache after those changes have been backed up at the datacenter server. Where this is the case, the client may be able to access the cached data later in connection with another request for a dataset. After the incremental has been stored 822 at the datacenter server, a table of contents can be created for the incremental, and the manifest updated 824.

E. Example Fuse Framework Methods

With reference now to FIG. 6, details are provided concerning aspects of a FUSE-specific method 900 for requesting and handling a virtual synthetic. The method 900 can begin when a FUSE module at a client requests 902 file system information. The request is received 904 at the datacenter server and the requested information is transmitted 906 by the datacenter server back to the client. The client receive 908 the file system information and then uses a FUSE interface of the FUSE module to present 910 the file system information in the form of a file system interface that represents a FUSE file structure.

The FUSE module then specifies 912 a byte range of a file in the file system that a user wishes to access. This byte range can be included in a request that includes both the byte range and the identification of the associated file. The request is sent 912 to the datacenter server which receives 914 the request and gathers the data in the specified byte range. The datacenter server then transmits 916 the requested data to the client. The requested data can form a virtual synthetic that includes respective data portions from a plurality of different backups residing at the datacenter server, where such backups can include a full backup and one or more incremental backups, for example.

After the client has received 918 the requested data, the FUSE module enables access to the virtual synthetic so that the user can perform 920 various operations with respect to the virtual synthetic. Once these operations are completed, the changes to the virtual synthetic can then be returned 922 to the datacenter server for backup as an incremental. The datacenter server 924 receives and backs up the changes to the virtual synthetic.

F. Example Computing Devices and Associated Media

The embodiments disclosed herein may include the use of a special purpose or general-purpose computer including various computer hardware or software modules, as discussed in greater detail below. A computer may include a processor and computer storage media carrying instructions that, when executed by the processor and/or caused to be executed by the processor, perform any one or more of the methods disclosed herein.

As indicated above, embodiments within the scope of the present invention also include computer storage media, which are physical media for carrying or having computer-executable instructions or data structures stored thereon. Such computer storage media can be any available physical media that can be accessed by a general purpose or special purpose computer.

By way of example, and not limitation, such computer storage media can comprise hardware such as solid state disk (SSD), RAM, ROM, EEPROM, CD-ROM, flash memory, phase-change memory (“PCM”), or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other hardware storage devices which can be used to store program code in the form of computer-executable instructions or data structures, which can be accessed and executed by a general-purpose or special-purpose computer system to implement the disclosed functionality of the invention. Combinations of the above should also be included within the scope of computer storage media. Such media are also examples of non-transitory storage media, and non-transitory storage media also embraces cloud-based storage systems and structures, although the scope of the invention is not limited to these examples of non-transitory storage media.

Computer-executable instructions comprise, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts disclosed herein are disclosed as example forms of implementing the claims.

As used herein, the term ‘module’ or ‘component’ can refer to software objects or routines that execute on the computing system. The different components, modules, engines, and services described herein may be implemented as objects or processes that execute on the computing system, for example, as separate threads. While the system and methods described herein can be implemented in software, implementations in hardware or a combination of software and hardware are also possible and contemplated. In the present disclosure, a ‘computing entity’ may be any computing system as previously defined herein, or any module or combination of modules running on a computing system.

In at least some instances, a hardware processor is provided that is operable to carry out executable instructions for performing a method or process, such as the methods and processes disclosed herein. The hardware processor may or may not comprise an element of other hardware, such as the computing devices and systems disclosed herein.

In terms of computing environments, embodiments of the invention can be performed in client-server environments, whether network or local environments, or in any other suitable environment. Suitable operating environments for at least some embodiments of the invention include cloud computing environments where one or more of a client, server, or target virtual machine may reside and operate in a cloud environment.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

What is claimed is:
 1. A method, comprising: performing the following operations at a server located at a datacenter and configured to service client requests: receiving, from a client, a request for file system information; transmitting the requested file system information to the client; receiving, from the client, a request for data comprising a portion of a file that resides at the datacenter, wherein the file is compatible for use by an application residing at the client, wherein the request for data specifies a particular byte range associated with the file, and wherein the byte range spans a plurality of different backups of a baseline dataset residing at the datacenter; creating a virtual synthetic that is formed by the data in the requested byte range and includes respective portions of data from each of the plurality of backups residing at the datacenter; and transmitting the virtual synthetic to the client.
 2. The method as recited in claim 1, wherein the request for file system information is received from a client Filesystem in Userspace (FUSE) interface of a FUSE module.
 3. The method as recited in claim 1, wherein the requested file system information is transmitted to a FUSE module of the client.
 4. The method as recited in claim 1, wherein the request for data is received from a FUSE module of the client.
 5. The method as recited in claim 1, wherein the virtual synthetic includes data from one of a mailbox file, a database, or a virtual machine (VM) disk file.
 6. The method as recited in claim 1, wherein the plurality of backups that contribute data to the virtual synthetic include one or more of an incremental backup, and a full backup.
 7. The method as recited in claim 1, wherein the request for data specifies the file as that file existed at a particular time.
 8. The method as recited in claim 1, wherein the portion of the file is less than the entire file.
 9. The method as recited in claim 1, further comprising encrypting the virtual synthetic before transmitting the virtual synthetic to the client.
 10. The method as recited in claim 1, wherein the virtual synthetic is created ad hoc at the datacenter in response to receipt of the request for data by the client.
 11. The method as recited in claim 1, further comprising receiving, from the client, a change to the virtual synthetic, and backing up the change to the virtual synthetic.
 12. A non-transitory storage medium having stored therein computer-executable instructions which, when executed by one or more hardware processors: perform the following operations at a server located at a datacenter and configured to service client requests: receiving, from a client, a request for file system information; transmitting the requested file system information to the client; receiving, from the client, a request for data comprising a portion of a file that resides at the datacenter, wherein the file is compatible for use by an application residing at the client, wherein the request for data specifies a particular byte range associated with the file, and wherein the byte range spans a plurality of different backups of a baseline dataset residing at the datacenter; creating a virtual synthetic that is formed by the data in the requested byte range and includes respective portions of data from each of the plurality of backups residing at the datacenter; and transmitting the virtual synthetic to the client.
 13. The non-transitory storage medium as recited in claim 12, wherein the requested file system information is transmitted to a FUSE module of the client.
 14. The non-transitory storage medium as recited in claim 12, wherein the request for data and/or the request for file system information is received from a FUSE module of the client.
 15. The non-transitory storage medium as recited in claim 12, wherein the virtual synthetic includes data from one of a mailbox file, a database, or a virtual machine (VM) disk file.
 16. The non-transitory storage medium as recited in claim 12, wherein the plurality of backups that contribute data to the virtual synthetic include one or more of an incremental backup, and a full backup.
 17. The non-transitory storage medium as recited in claim 12, wherein the request for data specifies the file as that file existed at a particular time.
 18. The non-transitory storage medium as recited in claim 12, wherein the portion of the file is less than the entire file.
 19. The non-transitory storage medium as recited in claim 12, wherein the virtual synthetic is created ad hoc at the datacenter in response to receipt of the request for data by the client.
 20. The non-transitory storage medium as recited in claim 12, wherein the operations further comprise: encrypting the virtual synthetic before transmitting the virtual synthetic to the client; and/or receiving, from the client, a change to the virtual synthetic, and backing up the change to the virtual synthetic. 